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PBDEs, an emerging group of persistent pollutants
Marine Pollution Bulletin 49 (2004) 369–370 www.elsevier.com/locate/marpolbul
Editorial
PBDEs, an emerging group of persistent pollutants
A group of man-made organic chemicals, increasingly used in the last few decades, polybrominated diphenyl ethers (PBDEs), have aroused concern because of their detection at significant levels in air, water, fish, marine and terrestrial mammals as well as in human breast milk. They now need to be included in the list of persistent organic pollutants (POPs). They have the potential to cause a global pollution problem similar to that caused by existing POPs, the 12 chemicals designated for immediate control or ban under the Stockholm Convention, which came into effect on 17th May 2004. PBDEs are now being widely used in a variety of consumer products as flame retardants to decrease the likelihood and intensity of fire in products including vehicles, computers, foam furniture, building materials, electrical and electronic equipment, in short, just about anywhere plastics are used. They have found their way into polystyrene, polyurethane and textile products as well. PBDEs are additive flame retardants and hence easily volatilize into atmosphere from the products in which they reside, and the environment and wildlife. Leaching from waste may thus be an important pathway of contamination. PBDEs are structurally similar to polychlorinated biphenyls (PCBs), chlorinated compounds with similar physical and chemical properties. It may be interesting to note that both groups of compounds are transportable in the same way and to the same extent through air and water. They are persistent in the environment, build up in living organisms and last a long time in animal bodies. Because of the chemical similarity of PBDEs to PCBs (and some other POPs), it has been suggested by several authors that all these compounds may be toxic, having terratogenic, mutagenic and carcinogenic effects on wildlife. While most POPs are now banned or are severely restricted in many countries under the Stockholm Convention, PBDEs still have unrestricted and widespread usage all over the world. Annual world produc-
0025-326X/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2004.07.015
tion and usage of PBDEs in 2001 was 67,440 tons. The worldwide demand was mainly distributed between North America (49%), Asia (37%) and Europe (12%). In this, out of the total amount of PBDEs consumed in the Asian region, the percent consumption by Japan was very much smaller, suggesting larger usage of PBDEs in the economically developing Asian world. PBDEs enter air, water and soil during their manufacture, and in the use and disposal of plastic products containing them, in waste sites. Exposure of the general population will be mainly from past and present releases. The exposure may be through air, water, sediments and food, and now they are ubiquitous. PBDEs now contaminate human milk, fatty tissues and serum. However the health problems that might be caused cannot be clearly established. We do not know whether PBDEs can cause health effects in human, even though it has been shown that they can cause liver cancer in rats and mice. PBDEs are potent thyroid disruptors. They alter the thyroid hormone homeostasis, and they have been suggested to disrupt brain development resulting in permanent neurologic damage in mice. Mice and rats exposed to PBDEs before and shortly after birth suffer permanent learning, memory and behavior disorders. PBDEs hamper mental development in rats by reducing thyroid hormone activity. Even though they have a chemical similarity to PCBs and other POPs they are far less studied in terms of both their distribution and from a toxicological perspective. Recent studies showed that PBDEs are present in the fish, skipjack tuna collected from a wide range of Asian waters and nearby seas, and also from remote seas and oceans around Asia, the Pacific, and around African and South American countries. PBDEs were also found to cause widespread contamination in dolphins and whales of tropical and temperate Asian coastal waters from countries like Japan, Hong Kong, the Philippines and India, as well as in northern fur seals from the northwestern North Pacific and in ringed seals of
370
Editorial / Marine Pollution Bulletin 49 (2004) 369–370
Canadian Arctic. Interestingly, in one of the studies, the highest concentrations of these chemicals were found in the East China Sea, with apparently higher levels than the waters around the developed nations such as Korea and Japan. Further to this fact, the global distribution of PBDEs is rather similar to that of DDTs in seas near developing as well as developed nations, plausibly as a result of their usage even in developing countries under economic reform. This may indicate, unlike the case of PCBs, that the source(s) principally occur in industrialized regions of the world; the major sources of PBDEs might be present not only in developed nations but also in the developing world with higher economic growth rates. In many cases, the fact that levels of PBDEs were very much lower than the classical organochlorines does not subvert possible future effects by these chemicals. In contrast, at a time when levels of organochlorines like PCBs, DDTs, PCDDs and PCDFs are going down in all the above animals from 1970s till today, PBDEs
are going up. If such a trend continues, PBDEs may surpass PCBs in a few decades to become the most prevalent organohalogen compound. Even though human toxic evaluations are yet to be made on these chemicals, would not the above cited facts be enough to demand evaluations on PBDEs in the global environment and biota, as was done for many of the chemicals now under control by the Stockholm Convention? It is time to include the PBDEs in the list of Persistent Organic Pollutants. Shinsuke Tanabe Center for Marine Environmental Studies Ehime University Bunkyo-cho 2-5 Matsuyama 790-8577 Japan Tel./fax: +81 89 927 8171 E-mail address: [email protected]
Editorial
PBDEs, an emerging group of persistent pollutants
A group of man-made organic chemicals, increasingly used in the last few decades, polybrominated diphenyl ethers (PBDEs), have aroused concern because of their detection at significant levels in air, water, fish, marine and terrestrial mammals as well as in human breast milk. They now need to be included in the list of persistent organic pollutants (POPs). They have the potential to cause a global pollution problem similar to that caused by existing POPs, the 12 chemicals designated for immediate control or ban under the Stockholm Convention, which came into effect on 17th May 2004. PBDEs are now being widely used in a variety of consumer products as flame retardants to decrease the likelihood and intensity of fire in products including vehicles, computers, foam furniture, building materials, electrical and electronic equipment, in short, just about anywhere plastics are used. They have found their way into polystyrene, polyurethane and textile products as well. PBDEs are additive flame retardants and hence easily volatilize into atmosphere from the products in which they reside, and the environment and wildlife. Leaching from waste may thus be an important pathway of contamination. PBDEs are structurally similar to polychlorinated biphenyls (PCBs), chlorinated compounds with similar physical and chemical properties. It may be interesting to note that both groups of compounds are transportable in the same way and to the same extent through air and water. They are persistent in the environment, build up in living organisms and last a long time in animal bodies. Because of the chemical similarity of PBDEs to PCBs (and some other POPs), it has been suggested by several authors that all these compounds may be toxic, having terratogenic, mutagenic and carcinogenic effects on wildlife. While most POPs are now banned or are severely restricted in many countries under the Stockholm Convention, PBDEs still have unrestricted and widespread usage all over the world. Annual world produc-
0025-326X/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2004.07.015
tion and usage of PBDEs in 2001 was 67,440 tons. The worldwide demand was mainly distributed between North America (49%), Asia (37%) and Europe (12%). In this, out of the total amount of PBDEs consumed in the Asian region, the percent consumption by Japan was very much smaller, suggesting larger usage of PBDEs in the economically developing Asian world. PBDEs enter air, water and soil during their manufacture, and in the use and disposal of plastic products containing them, in waste sites. Exposure of the general population will be mainly from past and present releases. The exposure may be through air, water, sediments and food, and now they are ubiquitous. PBDEs now contaminate human milk, fatty tissues and serum. However the health problems that might be caused cannot be clearly established. We do not know whether PBDEs can cause health effects in human, even though it has been shown that they can cause liver cancer in rats and mice. PBDEs are potent thyroid disruptors. They alter the thyroid hormone homeostasis, and they have been suggested to disrupt brain development resulting in permanent neurologic damage in mice. Mice and rats exposed to PBDEs before and shortly after birth suffer permanent learning, memory and behavior disorders. PBDEs hamper mental development in rats by reducing thyroid hormone activity. Even though they have a chemical similarity to PCBs and other POPs they are far less studied in terms of both their distribution and from a toxicological perspective. Recent studies showed that PBDEs are present in the fish, skipjack tuna collected from a wide range of Asian waters and nearby seas, and also from remote seas and oceans around Asia, the Pacific, and around African and South American countries. PBDEs were also found to cause widespread contamination in dolphins and whales of tropical and temperate Asian coastal waters from countries like Japan, Hong Kong, the Philippines and India, as well as in northern fur seals from the northwestern North Pacific and in ringed seals of
370
Editorial / Marine Pollution Bulletin 49 (2004) 369–370
Canadian Arctic. Interestingly, in one of the studies, the highest concentrations of these chemicals were found in the East China Sea, with apparently higher levels than the waters around the developed nations such as Korea and Japan. Further to this fact, the global distribution of PBDEs is rather similar to that of DDTs in seas near developing as well as developed nations, plausibly as a result of their usage even in developing countries under economic reform. This may indicate, unlike the case of PCBs, that the source(s) principally occur in industrialized regions of the world; the major sources of PBDEs might be present not only in developed nations but also in the developing world with higher economic growth rates. In many cases, the fact that levels of PBDEs were very much lower than the classical organochlorines does not subvert possible future effects by these chemicals. In contrast, at a time when levels of organochlorines like PCBs, DDTs, PCDDs and PCDFs are going down in all the above animals from 1970s till today, PBDEs
are going up. If such a trend continues, PBDEs may surpass PCBs in a few decades to become the most prevalent organohalogen compound. Even though human toxic evaluations are yet to be made on these chemicals, would not the above cited facts be enough to demand evaluations on PBDEs in the global environment and biota, as was done for many of the chemicals now under control by the Stockholm Convention? It is time to include the PBDEs in the list of Persistent Organic Pollutants. Shinsuke Tanabe Center for Marine Environmental Studies Ehime University Bunkyo-cho 2-5 Matsuyama 790-8577 Japan Tel./fax: +81 89 927 8171 E-mail address: [email protected]